(1) Field of the Invention
The present invention relates to antennas for use with an underwater vehicle, and more specifically to a buoyant cable antenna that is towed by a submerged underwater vehicle to allow communication coverage in an omnidirectional pattern in the frequency range of 10 MHz to 30 MHz that is preferably compatible with existing buoyant cable antenna deployment and retrieval systems.
(2) Description of the Prior Art
Radio frequency communication for submerged underwater vehicles is currently limited to unidirectional signal coverage. Buoyant cable antenna systems consisting of a single floating horizontal antenna element together with a floating transmission line have been and are currently in use that provide for the type of radio frequency communication described above. Unfortunately, unidirectional signal coverage provides limited utility. The radiation efficiency of the current buoyant cable antennas is very low since the horizontal antenna element, which is partially immersed in seawater, encounters wave tilt in order to radiate the vertically polarized signal necessary for surface wave propagation of the signal. What is needed is a buoyant cable antenna that provides a radiation pattern that is omnidirectional in azimuth.